android 自动播放Banner

先看一下效果图

支持本地图片以及网络图片or本地网络混合。

使用方式：

<com.jalen.autobanner.BannerView
android:id="@+id/banner"
android:layout_width="match_parent"
android:layout_height="230dip">
</com.jalen.autobanner.BannerView>

核心的实现代码

int length = mList.size();
View view = LayoutInflater.from(mContext).inflate(R.layout.banner_view,this,true);
LinearLayout ll = (LinearLayout) view.findViewById(R.id.ll_points);
vp= (ViewPager) view.findViewById(R.id.vp);
ll.removeAllViews();
LinearLayout.LayoutParams ll_parmas = new LinearLayout.LayoutParams(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT);
ll_parmas.leftMargin=5;
ll_parmas.rightMargin=5;
for(int i=0;i<length;i++){
ImageView img = new ImageView(mContext);
img.setLayoutParams(ll_parmas);
if(i==0){
img.setImageResource(R.mipmap.dot_focus);
}else{
img.setImageResource(R.mipmap.dot_blur);
}
ll.addView(img);
mImgs.add(img);

final ImageView imgforview = new ImageView(mContext);
imgforview.setOnClickListener(this);
imgforview.setScaleType(ImageView.ScaleType.FIT_XY);
if(mList.get(i).getType()==0){//本地图片
imgforview.setImageResource(mList.get(i).getDrawableforint());

}else{//网络
Glide.with(mContext).load(mList.get(i).getDrawableforurl()).diskCacheStrategy(DiskCacheStrategy.ALL).into(imgforview);
//                Glide.with(mContext).load(mList.get(i).getDrawableforurl()).listener(new RequestListener<String, GlideDrawable>() {
//                    @Override
//                    public boolean onException(Exception e, String model, Target<GlideDrawable> target, boolean isFirstResource) {
//                        Log.d("yu","Faile:"+e.toString());
//                        return false;
//                    }
//
//                    @Override
//                    public boolean onResourceReady(GlideDrawable resource, String model, Target<GlideDrawable> target, boolean isFromMemoryCache, boolean isFirstResource) {
//                            imgforview.setImageDrawable(resource);
//                        return false;
//                    }
//                }).into(imgforview);
//                Log.d("yu","url: "+mList.get(i).getDrawableforurl());
}
mViews.add(imgforview);
}

vp.setAdapter(new MyAdapter());
vp.addOnPageChangeListener(onPageChange);

自动轮播利用的是handler的postdelay方法。

private Runnable task = new Runnable() {
@Override
public void run() {
if(isAuto){
currentItem = currentItem%(mViews.size());
//                Log.d("yu","runalbe "+currentItem);
if(currentItem==0){
vp.setCurrentItem(currentItem,false);
}else{
vp.setCurrentItem(currentItem);
}
currentItem++;
mHandle.postDelayed(task,delaytime);
}else{
mHandle.postDelayed(task,delaytime);
}
}
};

利用isAuto判断是否正在自动轮播 如果为false 不自动切换item。isAuto赋值操作位于OnPageChangeListener的onPageScrollStateChanged方法中：

public void onPageScrollStateChanged(int state) {

switch (state){
case ViewPager.SCROLL_STATE_IDLE://用户什么都没有操作
isAuto=true;
currentItem = vp.getCurrentItem();
//                    Log.d("yu","IDLE"+currentItem);
//                    if(vp.getCurrentItem()==mViews.size()){
//                        vp.setCurrentItem(0,false);
//                    }
break;
case ViewPager.SCROLL_STATE_DRAGGING://正在滑动
isAuto =false;
break;
case ViewPager.SCROLL_STATE_SETTLING://滑动结束
isAuto=true;
break;

}
}

当状态为SCROLL_STATE_DRAGGING时 说明用户正在操作 ，看下源码中的解释：

/**
* Indicates that the pager is in an idle, settled state. The current page
* is fully in view and no animation is in progress.
*/
public static final int SCROLL_STATE_IDLE = 0;

/**
* Indicates that the pager is currently being dragged by the user.
*/
public static final int SCROLL_STATE_DRAGGING = 1;

/**
* Indicates that the pager is in the process of settling to a final position.
*/
public static final int SCROLL_STATE_SETTLING = 2;

大致意思呢就是 0代码没有任何操作。1页面正在被用户拖动。2代表成功切换至下一页面。

源码地址

点击跳转

有问题随时欢迎Issues;